Structure and method related to a power module using a hybrid spacer

ABSTRACT

A power module includes a spacer block, a thermally conductive substrate coupled to one side of the spacer block, and a semiconductor device die coupled to an opposite side of the spacer block. The spacer block includes a solid spacer block and an adjacent flexible spacer block. An inner portion of the device die is coupled to the solid spacer block, and an outer portion of the semiconductor device die is coupled to the adjacent flexible spacer block.

TECHNICAL FIELD

This description relates to packaging of power devices.

BACKGROUND

Modern high-power devices can be fabricated using advanced silicontechnology to meet high power requirements. These high-power devices(e.g., silicon power devices such as an insulated-gate bipolartransistor (IGBT), a fast recovery diode (FRD), etc.) may be packaged insingle-side cooling (SSC) or dual-side cooling (DSC) power modules.High-power devices that can deliver or switch high levels of power canbe used in, for example, vehicles powered by electricity (e.g., Electricvehicles (EVs), hybrid electric vehicles (HEVs) and plug-in-electricvehicles (PHEV)). The larger size and thicknesses of the high-powerdevice die can create problems such as die warpage and die damage duringpackaging of the high-power devices for use in circuit packages or powermodules (e.g., SSC or DSC power modules), or during stress tests of thefabricated high-power devices.

SUMMARY

In a general aspect, a module (e.g., a power device module) includes aspacer block coupled to a semiconductor device die. A thermallyconductive substrate (e.g., a direct bonded copper (DBC) substrate) iscoupled to a first side of the spacer block. The semiconductor devicedie is coupled to a second side, opposite the first side, of the spacerblock. The spacer block includes a solid spacer block and an adjacentflexible spacer block. An inner portion of the semiconductor device dieis coupled to the solid spacer block, and an outer portion of thesemiconductor device die is coupled to the adjacent flexible spacerblock. The adjacent flexible spacer block is configured to accommodatemechanical displacement of the semiconductor device die in the moduleinduced by coefficient of thermal expansion (CTE) mismatch of the modulecomponents.

In an aspect, the adjacent flexible spacer block at least partiallysurrounds the solid spacer block.

In an aspect, the adjacent flexible spacer block is a strip attached to,and extending from, a side of the solid spacer block toward an edge ofthe device die.

In an aspect, the adjacent flexible spacer block is coupled to a signalpad region at the edge of the device die.

In an example implementation, the adjacent flexible spacer block has acorrugated structure made of at least one of a straight fin, a tiltedfin, a bent fin, a curved fin, or an S-shaped fin.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a block diagram illustrating an example hybrid spacer block.

FIG. 1B is a block diagram illustrating an example power moduleutilizing a hybrid spacer block for a die-supporting spacer blockcombination.

FIG. 2A illustrates a solid block.

FIGS. 2B through 2F illustrate different types of flexible spacerconfigurations that can be used in a hybrid spacer block.

FIG. 3 illustrates an example hybrid spacer block.

FIG. 4 illustrates an example method for assembling a hybrid spacerblock.

FIGS. 5A through 51 illustrate a hybrid spacer block at different stagesof assembly by the method of FIG. 4.

FIG. 6 illustrates an example method for assembling a hybrid spacerblock.

FIGS. 7A through 7D illustrate a hybrid spacer block at different stagesof assembly by the method of FIG. 6.

FIG. 8 shows schematic depicting relative sizes of an individual die, asolid spacer block, and a flexible spacer block.

FIG. 9 is a schematic illustration of hybrid spacer blocks for use in amulti-die power module.

FIG. 10 is a schematic illustration an arrangement of hybrid spacerblocks that may be individually coupled to a first device die and asecond device die in a multi-die power module.

FIG. 11 is a schematic illustration of a hybrid spacer block coupled toa first device die and a second device die in a multi-die power module.

FIG. 12 is a schematic of a hybrid spacer block coupled to a firstdevice die and a second device die in a multi-die power module.

FIG. 13 illustrates an example method of using a flexible spacer blockin a power module.

DETAILED DESCRIPTION

Modern high-power semiconductor devices can be fabricated using advancedsilicon technologies to meet the high power requirements. The powerdevices (e.g., an insulated-gate bipolar transistor (IGBT), a fastrecovery diode (FRD), etc.) may be fabricated using, for example, one ormore of silicon (Si), silicon carbide (SiC), and gallium nitride (GaN)materials, or other semiconductor materials. The power devices may befabricated on thinned semiconductor wafers (e.g., silicon wafers) thatare, for example, only about 100 microns thick or less. This results inhigh-power device die sizes that are larger and thinner than powerdevice die sizes for traditional power devices fabricated on regularsubstrates (i.e., on un-thinned silicon wafers) using conventionalsilicon technologies.

In circuit packages (e.g., a dual-side cooling (DSC) power module), thesemiconductor device die can be placed between a pair of direct bondedcopper (DBC) substrates that help conduct heat away from thesemiconductor device die. The individual thinned device die can bemechanically and structurally reinforced by bonding (e.g. soldering) asupporting spacer block (i.e., a thermally conducive spacer block) to abackside of the die. The spacer also provides good electrical isolationand thermal performance. The other side of the supporting spacer blockcan be bonded to a DBC substrate. The supporting spacer block provides athermal pathway for heat flow from the semiconductor device die to theDBC substrate. In a DSC power module, the die-supporting blockcombination is placed between the between the pair of DBC substrates andencapsulated in molding material (e.g., epoxy molding compound (EMC). Ininstances in which the die is placed in a flip-chip configuration on aDBC substrate, a molded underfill (MUF) molding material can beintroduced to underfill a narrow gap under the flip-chip die, and overmolding the die-supporting block combination for encapsulation.

In some implementations, the supporting spacer block is a solid piece ofthermally conductive material (e.g., a rectangular solid copper blockhaving a cross sectional area A and a thickness T). The thickness of thethin device die is augmented by the thickness of the solid copper blockin the die-supporting spacer block combination. The solid copper blockcan have a smaller cross sectional area than the area of device die orcan have a larger cross sectional area that may be comparable to thearea of the device die, However, cracks in the die can form around thesolid copper block when the block area is smaller than die area. Use ofsolid copper blocks that have larger areas (e.g., greater or comparableto the area of the device die) has been proposed as a remedy, but largearea solid copper blocks also result in die cracking. Solder voids mayform between a larger area solid copper block and die in thedie-supporting spacer block combination. These solder voids can inducedie corner cracks at die corners.

A cause of the die corner cracks may be a coefficient of thermalexpansion (CTE) mismatch between the spacer block (e.g., a copper block)and the MUF (or EMC) used in the die-supporting spacer blockcombination. As the copper spacer block shrinks faster than the MUF (orEMC) on cooling, the MUF (or EMC) will oppose the die motion induced byshrinkage of the solid copper spacer block at a die corner with thesolder voids and lead to stress that creates the die corner cracks.

In accordance with the principles of the present disclosure, a hybridspacer block for a die-supporting spacer block combination has a hybridstructure that includes a solid block spacer portion and a mechanicallyelastic or flexible block spacer portion. The solid spacer block portionmay have a cross sectional area that is smaller than the die area. Thesolid spacer block portion may be an inner portion (central portion) ofthe hybrid spacer block. The flexible block spacer portion may bedisposed around (e.g., surrounding, or adjacent) the solid spacer blockportion. The flexible spacer block portion and the solid spacer blockportion in combination may have a cross sectional area that iscomparable to or greater than the die area. In the die-supporting spacerblock combination, the flexible spacer block portion may extend to thedie corners and may flexibly accommodate any mechanical displacementsdue to CTE mismatch between the components (e.g., metal, EMC and diesemiconductor). This flexible accommodation of mechanical displacementsdue to CTE mismatch may prevent die cracking at die corners, and reduceinstances of solder peeling failure under the device pads (e.g., signalpads) in a DSC power module that utilizes the die-supporting spacerblock combination.

FIG. 1A shows a cross sectional view of an example hybrid spacer block140, in accordance with the principles of the present disclosure. Thehybrid spacer block 140 may include a solid metal block 142 (e.g., asolid copper block) that is surrounded (e.g., entirely surrounds, atleast partially surrounds) by a flexible spacer block 144 (e.g., amechanically flexible copper block). Solid metal block 142 may have awidth Ws. Hybrid spacer block 140 including flexible spacer block 144may have width Wf. Solid metal block 142 and flexible spacer block 144may be disposed between metal sheets 146 and 147 (e.g., copper sheets orfoils) and held in place between metal sheets 146 and 147 by solder(e.g., solder 14).

FIG. 1B shows a cross sectional view of an example DSC power module 100utilizing a hybrid spacer block 140 in a die-supporting spacer blockcombination, in accordance with the principles of the presentdisclosure. The example DSC power module 100 can utilize the hybridspacer block 140 discussed in connection with at least FIG. 1A.

DSC power module 100 may enclose a device die 130 and a hybrid spacerblock 140 between two DBC substrates (e.g., DBC substrate 110 and DBCsubstrate 120). On one side the hybrid spacer block (e.g., hybrid spacerblock 140) is coupled to the device die 130, and on another side thehybrid spacer block is bonded to one of the two DBC substrates (e.g.,DBC substrate 110). The hybrid spacer block provides a thermal pathwayfor heat generated in the device die to be dissipated over DBC substrate110.

Hybrid spacer block 140 may include a solid metal block 142 (e.g., asolid copper block) that is surrounded by a flexible spacer block 144(e.g., a mechanically flexible copper block). Solid metal block 142 andflexible spacer block 144 may be disposed between metal sheets 146 and147 (e.g., copper sheets or foils) and held in place between metalsheets 146 and 147 by solder (e.g., solder 14). Device die 130 (e.g., anIGBT device) may be bonded (e.g., soldered) to hybrid spacer block 140via a solder layer 15 forming a die-spacer block combination 150 of DSCpower module 100. An inner portion of device die 130 may be bonded tosolid metal block 142. An outer portion of the device die (e.g.,extending from the inner portion to an edge E of the device die) may bebonded to the flexible spacer block 144. In example implementations, asshown in FIG. 1B, hybrid spacer block 140 may have a width Wsp that isabout a same or greater that a width Wdie of device die 130. In thisgeometrical arrangement, any displacement of device die edge E (e.g.,device die bending induced by thermal mismatch of components) can beaccommodated (e.g., mechanically) by the elasticity of flexible spacerblock 144 and die cracking can be prevented.

In example implementations, as shown in FIG. 1B, DBC substrate 110 andDBC substrate 120 may be ceramic tiles (e.g., alumina tiles 112, 122)that are plated with copper layers (e.g., layers 114, 124). Device die130 (e.g., an IGBT device) may have one or more contact pads (e.g.,signal pads 132 and source pads 133).

In example implementations, as shown in FIG. 1B, DSC power module 100may be assembled, for example, with die-spacer block combination 150 inan orientation that has device 130 in a flip chip configuration. Device130 in the flip chip configuration may have signal pads 132 and sourcepads 133 bonded to DBC substrate 120 via a solder layer 16. Further,hybrid spacer block 140 (of die-spacer block combination 150) may bebonded to DBC substrate 110 via a solder layer 17.

The mechanically elastic or flexible spacer material used for flexiblespacer block 144 in hybrid spacer block 140 can be of different types.FIGS. 2B through 2G show cross sectional views of different types offlexible spacer configurations that may be used in hybrid spacer block140. FIG. 2A shows, for comparison, a cross sectional view of solidmetal block 142.

FIG. 2B illustrates example flexible spacer material 200B that includesa corrugated structure 201S made of straight fins (e.g., straight fin201). As pictorially shown in FIG. 2B, the straight fins may be arrangedso that corrugated structure 201S is made of alternate rectangularridges 201 r and grooves or valleys 201 v with vertical sidewalls 201 swformed by the straight fins 201. Ridges 201 r and valleys 201 s mayalternate with a spatial periodicity Wv. Valleys 201 v with verticalsidewalls 201 sw may have a height Tv.

FIG. 2C illustrates example flexible spacer material 200C that includesa corrugated structure 202S made of tilted fins (e.g., tilted fin 202).As pictorially shown in FIG. 2C, the tilted fins may be arranged so thatcorrugated structure 202S is made of alternate ridges 202 r and groovesor valleys 202 v with slanted or tilted sidewalls 202 sw formed by thetilted fins 202.

FIG. 2D illustrates example flexible spacer material 200D that includesa corrugated structure 203S made of bent fins (e.g., bent fin 203). Aspictorially shown in FIG. 2C, the bent fins may be arranged so thatcorrugated structure 203S is made of alternate ridges 203 r and groovesor valleys 202 v formed by bent fins 203 with bent sidewalls 203 sw

FIG. 2E illustrates example flexible spacer material 200E that includesa corrugated structure 204S made of curved fins (e.g., curved fin 204).As pictorially shown in FIG. 2E, the curved fins may be arranged so thatcorrugated structure 204S is made of alternate rectangular ridges 204 rand grooves or valleys 204 v formed by curved fins 204 with curvedsidewalls 204 sw.

FIG. 2F illustrates example flexible spacer material 200F that includesa corrugated structure 205S made of S-shaped fins (e.g., S-shaped fin205). As pictorially shown in FIG. 2F, the S-shaped fins may be arrangedso that corrugated structure 205S is made of alternate rectangularridges 205 r and grooves or valleys 205 v formed by S-shaped fins 204with S-shaped sidewalls 205 sw.

The different types of flexible spacer material with the different typesof fin structure (e.g., straight fin 101, tilted fin 202, bent fin 203,curved fin 204, and S-shaped fin 205, etc.) may impart differentmechanical and thermal properties to flexible spacer block 144.

FIGS. 1A and 1B, as discussed above, show, for example, animplementation in which flexible spacer block 144 is made of flexiblespacer material of the S-shaped fin type (i.e., S-shaped fin 205).

FIG. 3 shows, for example, an implementation in which hybrid spacerblock 140 uses material of the straight fin type (i.e., straight fin201) for flexible spacer block 144. As shown in FIG. 3, in hybrid spacerblock 140, flexible spacer block 144 may surround and be coupled to asolid spacer block (e.g., solid spacer block 142).

FIG. 4 shows an example method 400 for assembling a hybrid spacer block(e.g., hybrid spacer block 140) for use in die-spacer block combinationin a power module.

Method 400 includes shaping a block of flexible spacer material tospecified outer dimensions of the hybrid spacer block and preparing aninner portion of the block of flexible spacer material to accommodatespecified dimensions of a solid metal block (410). The specified outerdimensions of the hybrid spacer block may match the dimensions of thesemiconductor die in the die-spacer block combination.

Preparing the inner portion of the block of flexible spacer material toaccommodate specified dimensions of a solid metal block 410 may includeremoving a portion of the block of flexible spacer material to create anopening (e.g. by cutting out a hole) in the block of flexible spacermaterial. Preparing the inner portion may include adding side foilpanels (e.g., copper foil) to the opening or hole.

Method 400 may further include applying a first bonding material (e.g.,a solder) to a bottom sheet of metal (e.g., a copper foil) (420),placing the shaped block of flexible spacer material and the solid blockof metal on the first bonding material applied to the bottom sheet ofmetal (430). Method 400 further includes applying a second bondingmaterial (e.g., a solder) to top surfaces of the shaped block offlexible space material and the solid block of metal disposed on thebottom sheet of metal (440), placing a top sheet of metal (e.g., copperfoil) over the second bonding material (450), and reflowing the solderand curing the assembly to form the hybrid spacer block (460).

FIGS. 5A through 5I show the hybrid spacer block (e.g., hybrid spacerblock 140) at different stages of assembly by method 400 starting with ablock of flexible spacer material 500.

FIGS. 5A and 5B show a starting block of flexible spacer material 500that can be utilized to make hybrid spacer block 140 according to method400. In an example implementation, flexible spacer material 500 may havea straight fin structure, i.e., a corrugated structure 148 made ofalternate rectangular ridges 501 and grooves 502 with verticalsidewalls.

FIG. 5A shows a top view of flexible spacer material 500 having, forexample, rectangular slab dimensions D1×D2 and a thickness D3. Inexample implementations, the dimensions D1 and D2 each may be greaterthan about 10 millimeters, and thickness D3 may be in the range of 0.5to 3.0 millimeters.

FIG. 5B shows a cross sectional view of starting block of flexiblespacer material 500 depicting the ridges and grooves of corrugatedstructure 148 having a thickness D3. Corrugated structure 148 may beformed, for example, by rippling a thin metallic sheet (e.g., a coppersheet) having a thickness t1 to form ridges 501 and grooves 502. Inexample implementations, the thickness t1 may be in the range of 0.05 to3.0 millimeters. Each cell of the corrugated structure (i.e., ridge-toridge distance) may have a spacing C. In example implementations,spacing C may be in the range of 0.5 to 2 millimeters.

FIGS. 5C and 5D show a block of solid material (e.g., solid metal block142) that can be used in hybrid spacer block 140, according to method400. FIG. 5C shows a top view of solid metal block 142 having, forexample, rectangular slab dimensions W1×L1. FIG. 5D shows a side view ofsolid metal block 142 having, for example, a thickness D4. In exampleimplementations, the dimensions W1 and L1 each may be smaller than about50 millimeters, and thickness D4 may be in the range of 0.5 to 3.0millimeters.

FIG. 5E shows flexible spacer block 144 that has been shaped (fromflexible spacer material 500) to specified outer dimensions of thehybrid spacer block (e.g., at 410, method 400). Flexible spacer block144 may, for example, have a width W, a length L, and a thickness T thatcorrespond to specified outer dimensions of the hybrid spacer block 140.Further, an open inner portion 145 of flexible spacer block is cut outto accommodate specified dimensions of solid metal block 142 of hybridspacer block 140. Inner portion 145 may, for example, have rectangulardimensions L1×W1 matching the dimension of solid metal block 142 (FIG.5C).

FIG. 5F shows a first bonding material (e.g., solder 14) being appliedto a metal sheet 146 that may form a bottom support for flexible spacerblock 144 and solid metal block 142 in hybrid spacer block 140 (e.g., at420, method 400).

FIG. 5G shows flexible spacer block 144 and solid metal block 142assembled on bottom metal sheet 146 with solid metal block 142 placed ina hole (e.g., open inner portion 145) in flexible spacer block 144(e.g., at 430, method 400).

FIG. 5H shows a second bonding material (e.g., a solder 14) applied totop surfaces of the shaped block of flexible spacer material and thesolid block of metal disposed on the bottom sheet of metal 146 (e.g., at440, method 400).

FIG. 51 shows a top sheet of metal (e.g., metal sheet 147) placed overthe second bonding material of the assembly of FIG. 5F (e.g., at 450,method 400). The assembly may be heated for solder reflow and curing tobond the top and bottom metal sheets 146, 147 to the assembly componentsand, thus, form hybrid spacer block 140).

In an example implementations discussed above with reference to FIGS.5A-5I, flexible spacer material 500 has a straight fin structure (i.e.,a corrugated structure 148 made of alternating rectangular ridges 501and grooves 502 with vertical sidewalls). In other implementations,flexible spacer material 500 may have other types of flexible structureswith non-vertical sidewalls (e.g., tilted fin 202, bent fin 203, curvedfin 204, and S-shaped fin 205, etc., shown in, for example, FIGS. 2Bthrough 2F).

FIG. 6 shows an example method 600 for assembling a hybrid spacer block(e.g., hybrid spacer block 140) using starting flexible materials thathave flexible structures that have non-vertical walls (e.g., a structurewith S-shaped fin 205). In such spacer materials, the flexible fins(e.g., S fins) may be pre-attached to a bottom foil.

Method 600 includes shaping a block of flexible spacer material tospecified outer dimensions of the hybrid spacer block (610) and removingan inner portion of the block of flexible spacer material to create anopening that can accommodate specified dimensions of a solid metal block(620), and coupling (e.g., adding) vertical side foil panels to theopening (630).

Method 600 further includes dispensing a bottom solder layer on thebottom foil in the opening and placing the solid block of metal on thebottom solder layer in the opening (640). Method 600 further includesdispensing a side solder layer in a space between the vertical side foilpanels and the solid block of metal, and a top solder layer on top ofthe assembly (650), and placing a top sheet of metal (e.g., copper foil)over the assembly (660), and reflowing the solder and curing theassembly to form the hybrid spacer block (670).

FIGS. 7A through 7D show the hybrid spacer block (e.g., hybrid spacerblock 140) at different stages of assembly by method 600 starting with ablock of flexible spacer material with S-shaped fins.

FIG. 7A shows a cross sectional view a block of flexible spacer material700 shaped to specified outer dimensions of the hybrid spacer block.Flexible spacer material 700 may have a S-shaped fin structure (i.e., acorrugated structure 748 made of alternate ridges 701 and grooves 702formed by S-shaped fins 744 with non-vertical vertical sides). TheS-shaped fins may be attached to a bottom metal sheet 746.

FIG. 7B shows a cross sectional view of the block of flexible spacermaterial 700 after removal of an inner portion of the block to create anopening 745, and the adding of vertical side foil panels 747 to opening745. The dimensions of opening 745 may match the dimensions of solidmetal block 142.

FIG. 7C shows a solder layer 14-1 dispensed on bottom metal sheet 746and solid metal block 142 placed on solder layer 14-2 in opening 745.

FIG. 7D shows a solder layer 14-2 introduced in a space between verticalside foil panels 747 and the solid metal block 142 in opening 745, and asolder layer 14-3 dispensed on top of the assembly. Further, a top sheetof metal (e.g., metal sheet 147) is placed over solder layer 14-3 on topof the assembly. The assembly may be heated for solder reflow and curingof solder layers 14-1, 14-2, and 14-3 to bond the top and bottom metalsheets 146, 147 to the assembly components and, thus, form hybrid spacerblock 140.

In example implementations, the hybrid spacer blocks described hereinthan include both a solid block portion and a flexible block portion canimprove the reliability of power modules. The flexible block portion ofa hybrid spacer block can accommodate mechanical displacements ofcomponents induced by CTE mismatch between components and reduce diestress and solder peeling strain in the power module. The solid blockportion can be used meet thermal and electrical performance requirementsof the power module. Mechanical, thermal, and electrical performance ofthe power module can be optimized by adjusting the size, shape, andmaterial of the solid block portion. A design of the flexible portion ofthe spacer (i.e., corrugated, fin, Z-shape, etc.) can also be used totune the mechanical, thermal, and electrical performancecharacteristics.

Example power modules may include one or more power device dies (e.g.,an IGBT and an FRD) that are coupled via the hybrid spacer blocks to DSCsubstrates. The hybrid spacer blocks may include flexible spacer blocksthat are different (i.e. bigger or smaller) in size than the individualdie size. FIG. 8 shows a diagram in which blocks representing anindividual die 801, a solid spacer block 802, and a flexible spacerblock 803 are overlaid for size comparison. Individual die 801 may havea characteristic size A, solid spacer block 802 may have acharacteristic size B, and flexible spacer block 803 may havecharacteristic size C.

In example implementations, the die size A may be in the range of about10 to 14 millimeters, and the flexible spacer block size C may be in therange of about 12 to 17 millimeters. Further, the hybrid spacer blocksmay include solid spacer blocks that are different (e.g., smaller orequal) in size than the die size A. In example implementations, thesolid spacer block size B may, for example, be in the range of about 6to 10 millimeters for die size in the range of about 10 to 14millimeters.

In example implementations of the hybrid spacer block (e.g., hybridspacer block 140) discussed above with reference to FIGS. 1 through 8,the flexible spacer block surrounds the solid block portion. In adie-spacer block combination (e.g., die-spacer block combination 150),the flexible spacer block extends toward the die edges and canaccommodate CTE mismatch stresses which may be pronounced at the dieedges compared to the stresses at the die center. Each die in amulti-die power module may be coupled to a respective die-spacer blockcombination. FIG. 9 shows, for example, hybrid spacer 910 and hybridspacer 920 that may be individually coupled to a first die (e.g., anIGBT) (not shown) and a second die (e.g., an FRD) (not shown) in amulti-die power module. Hybrid spacer 910 may include a solid metalblock 912 surrounded by a flexible spacer block 914 coupled to the firstdie (e.g., an IGBT). Hybrid spacer 920 may include a solid metal block922 surrounded by a flexible spacer block 924 coupled to the second die(e.g., an FRD).

In other implementations, hybrid spacer material (e.g., straight fin201, tilted fin 202, bent fin 203, curved fin 204, and S-shaped fin 205)may be incorporated in a hybrid spacer block in different geometries(e.g., other than surrounding a single solid metal block on all sides).FIGS. 10 through 12 shows examples of different geometries of hybridspacer material used in hybrid spacer blocks

FIG. 10 shows, for example, an arrangement of hybrid spacer blocks 1010and 1020 that may be individually coupled to a first device die 1001(e.g., an IGBT) and a second device die 1002 (e.g., an FRD) in amulti-die power module. First device die 1001 may include a signal padregion 1005 including signal pads 1001 a associated with the IGBT.

Hybrid spacer block 1010 may include a solid metal block 1012 and aflexible spacer block 1014. Solid metal block 1012 may be comparable insize to device die 1001 (e.g., an IGBT). Flexible spacer block 1014 maybe a rectangular strip having a width WS. Flexible spacer block 1014 asa strip may be attached to, and extend from, a side of solid metal block1012. Flexible spacer block 1014 may extend from the side of solid metalblock 1012 to support (i.e., be bonded to) only signal pad region 1005of first device die 1001, while solid metal block 1012 may support theremainder of the die in a die-spacer block combination.

In the example of FIG. 10, spacer block 1020 (that forms a die-spacerblock combination with second device die 1002 (e.g., an FRD)) mayinclude only a solid metal block 1012 and no flexible spacer block.

FIG. 11 shows, for example, a hybrid spacer block 1130 that may becoupled to both first device die 1001 (e.g., an IGBT) and second devicedie 1002 (e.g., an FRD) in a multi-die power module. First device die1001 may include a signal pad region 1005 and a source pad 1001 b.Second device die 1001 may include a source pad 1002 b. Hybrid spacerblock 1130 may include a single solid metal block 1132 that can form adual die-spacer block combination with first device die 1001 and seconddevice die 1002. Hybrid spacer block 1030 may, like hybrid spacer block1010 (FIG. 10), further include flexible spacer block 1014 extendingfrom a side of solid metal block 1130 to support only signal pad region1005 of first device die 1001,

FIG. 12 shows, for example, a hybrid spacer block 1240 that may becoupled to both first device die 1001 (e.g., an IGBT) and second devicedie 1002 (e.g., an FRD) in a multi-die power module. Hybrid spacer block1240 may, like hybrid spacer blocks 1010 and 1020 (FIG. 10), include afirst sub-block (i.e., a solid metal block 1212) and a second sub-block(i.e., a solid metal block 1222) that can be individually coupled tofirst device die 1001 and second device die 1002, respectively. Hybridspacer block 1240 may further include a single flexible spacer block1214 that supports signal pad region 1005 of first device die 1001 andextends away continuously from signal pad region 1005 to surround solidmetal block 1212 and solid metal block 1222.

FIG. 13 shows an example method for using a flexible spacer block in apower module to accommodate component displacement that may occur, forexample, due to CTE mismatch. The power module may include one or moredevice die (e.g., a FRD, an IGBT, etc.).

Method 1300 includes coupling an inner portion of a semiconductor devicedie to a solid spacer block (1310), disposing a flexible spacer blockadjacent to the solid spacer block (1320), and coupling an edge portionof the semiconductor device die to the flexible spacer block (1330).

In method 1300, disposing a flexible spacer block adjacent to the solidspacer block can include disposing the solid spacer block in an openingin the flexible spacer block. Further, disposing a flexible spacer blockadjacent to the solid spacer block can, alternatively or additionally,include disposing the flexible spacer block as strip attached to, andextending from, a side of the solid spacer block.

In method 1300, coupling the edge portion of the semiconductor devicedie to the flexible spacer block may include coupling the flexiblespacer block to a signal pads region at the edge of the device die.

It will be understood that, in the foregoing description, when anelement, such as a layer, a region, a substrate, or component isreferred to as being on, connected to, electrically connected to,coupled to, or electrically coupled to another element, it may bedirectly on, connected or coupled to the other element, or one or moreintervening elements may be present. In contrast, when an element isreferred to as being directly on, directly connected to or directlycoupled to another element or layer, there are no intervening elementsor layers present. Although the terms directly on, directly connectedto, or directly coupled to may not be used throughout the detaileddescription, elements that are shown as being directly on, directlyconnected or directly coupled can be referred to as such. The claims ofthe application, if any, may be amended to recite exemplaryrelationships described in the specification or shown in the figures.

As used in the specification and claims, a singular form may, unlessdefinitely indicating a particular case in terms of the context, includea plural form. Spatially relative terms (e.g., over, above, upper,under, beneath, below, lower, and so forth) are intended to encompassdifferent orientations of the device in use or operation in addition tothe orientation depicted in the figures. In some implementations, therelative terms above and below can, respectively, include verticallyabove and vertically below. In some implementations, the term adjacentcan include laterally adjacent to or horizontally adjacent to.

Some implementations may be implemented using various semiconductorprocessing and/or packaging techniques. Some implementations may beimplemented using various types of semiconductor processing techniquesassociated with semiconductor substrates including, but not limited to,for example, Silicon (Si), Gallium Arsenide (GaAs), Gallium Nitride(GaN), Silicon Carbide (SiC) and/or so forth.

While certain features of the described implementations have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art. Itis, therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the scope of theimplementations. It should be understood that they have been presentedby way of example only, not limitation, and various changes in form anddetails may be made. Any portion of the apparatus and/or methodsdescribed herein may be combined in any combination, except mutuallyexclusive combinations. The implementations described herein can includevarious combinations and/or sub-combinations of the functions,components and/or features of the different implementations described.

What is claimed is:
 1. A module, comprising: a spacer block including a solid spacer block and an adjacent flexible spacer block; a thermally conductive substrate coupled to a first side of the spacer block; a semiconductor device die coupled to a second side, opposite the first side, of the spacer block; and an inner portion of the semiconductor device die being coupled to the solid spacer block, and an outer portion of the semiconductor device die being coupled to the adjacent flexible spacer block.
 2. The module of claim 1, wherein the solid spacer block provides a thermal pathway for heat flow from the coupled semiconductor device die to the thermally conductive substrate.
 3. The module of claim 1, wherein the thermally conductive substrate is a direct bonded copper (DBC) substrate.
 4. The module of claim 1, wherein the adjacent flexible spacer block is configured to accommodate mechanical displacement of the semiconductor device die in the module induced by coefficient of thermal expansion (CTE) mismatch.
 5. The module of claim 1, wherein the adjacent flexible spacer block has a corrugated structure made of at least one of a straight fin, a tilted fin, a bent fin, a curved fin, or an S-shaped fin.
 6. The module of claim 1, wherein the adjacent flexible spacer block at least partially surrounds the solid spacer block.
 7. The module of claim 1, wherein the adjacent flexible spacer block is a strip attached to, and extending from, a side of the solid spacer block toward an edge of the device die.
 8. The module of claim 1, wherein the adjacent flexible spacer block is coupled to a signal pad region at the edge of the device die.
 9. The module of claim 1, wherein the adjacent flexible spacer block has a corrugated structure made of at least one of a straight fin, a tilted fin, a bent fin, a curved fin, or an S-shaped fin.
 10. The module of claim 1, wherein the solid spacer block and the adjacent flexible spacer block are disposed between a plurality of metal sheets and fixedly coupled in place between the metal sheets by solder.
 11. The module of claim 1, wherein the semiconductor device die includes at least one of a fast recovery diode (FRD) or an insulated gate bipolar transistor (IGBT).
 12. A method, comprising: coupling an inner portion of a semiconductor device die to a solid spacer block; disposing a flexible spacer block adjacent to the solid spacer block; and coupling an edge portion of the semiconductor device die to the flexible spacer block.
 13. The method of claim 12, wherein the disposing the flexible spacer block adjacent to the solid spacer block includes disposing the solid spacer block in an opening in the flexible spacer block.
 14. The method of claim 12, wherein the disposing the flexible spacer block adjacent to the solid spacer block includes disposing the flexible spacer block as strip attached to, and extending from, a side of the solid spacer block.
 15. The method of claim 14, wherein the coupling the edge portion of the semiconductor device die to the flexible spacer block includes coupling the flexible spacer block to a signal pads region at the edge of the device die.
 16. The method of claim 14, wherein the device die includes at least one of a fast recovery diode (FRD) or an insulated gate bipolar transistor (IGBT).
 17. A module, comprising: a first device die and a second device die, the first device die having an edge portion including at least one signal pad; and a spacer block including a solid spacer block coupled to a flexible spacer block, the solid spacer block being coupled to the first device die and the second device die, the flexible spacer block being coupled to the edge portion including at least one signal pad.
 18. The module of claim 17, wherein the solid spacer block includes a first sub-block coupled to the first device die and a second sub-block coupled to the second device die, and the flexible spacer at least partially surrounds the first sub-block and at least partially surrounds the second sub-block.
 19. The module of claim 17, wherein the flexible spacer block coupled to the edge portion of the first device die extends away continuously from the edge portion to at least partially surround the first sub-block and at least partially surround the second sub-block.
 20. The module of claim 17, wherein the first device die includes an insulated gate bipolar transistor (IGBT). 